Marine life such as acorn barnacle, mussel and algae tend to adhere to underwater structures such as a marine vessel, a fishing net and the like, and this causes a problem of interfering with efficient navigations to result in a waste of fuel in the marine vessels and a problem of clogging a net or shortening a useful life of a net in the fishing nets. In order to prevent the marine life from adhering to these underwater structures, an antifouling coating composition is generally applied onto the surfaces of the underwater structures as described in Japanese Kokai Publication Sho62-57464.
On the other hand, when like marine vessels, coating is applied to a location where friction occurs between the vessel and liquid, it is desired to reduce frictional resistance between the vessel and liquid by a coated film from the viewpoint of a reduction in navigation fuel to be consumed of the marine vessels and energy conservation.
A coating composition aimed at reducing such frictional resistance is disclosed in Japanese Kokai Publication Hei11-29725, Japanese Kokai Publication Hei11-29747, Japanese Kokai Publication 2001-98007, Japanese Kokai Publication Hei11-256077, Japanese Kokai Publication Hei10-259347 and Japanese Kokai Publication 2003-277691. In these patents, a resin composition for a coating composition, which uses a polymer such as an acrylic resin, a polyoxyethylene chain-containing polymer, an allylamine resin, chitin or chitosan as a resin binder in a coating composition, is disclosed.
But, these coating compositions are not those which reduce frictional resistance by resin particles added to a coated film.
In Japanese Kokai Publication Hei5-86309 and Japanese Kokai Publication Hei5-112741, it is described that a coated film of low frictional resistance can be attained by forming a coated film with an antifouling coating composition in which inorganic fine particles are mixed. However, these coated films have some frictional resistance effects in marine vessels moving at a low speed but they cannot attain adequate frictional resistance effects in marine vessels moving at a high speed and their effects are insufficient.